1. Field of the Invention
The present invention relates generally to plasma arc reactors and systems. More particularly, the present invention relates to a modular plasma arc reactor and related methods of creating hybrid arc plasmas to gasify heterogeneous materials to produce synthesis gas. A synthesis gas consists mainly of carbon monoxide (CO) and hydrogen (H2).
2. Prior Art Description
A plasma is commonly defined as a collection of charged particles containing equal numbers of positive ions and electrons, as well as excited neutrals. Although exhibiting some properties of a gas, a plasma is also a good conductor of electricity and can be affected by a magnetic field. One way to generate a plasma is to pass a gas through an electric arc. The arc heats the gas by resistive and radiative heating to very high temperatures within a fraction of a second. Essentially, any gas may be used to produce a plasma in such a manner. Thus, inert or neutral gases (e.g., argon, helium, neon, or nitrogen) may be used. Reductive gases (e.g., hydrogen, methane, ammonia, or carbon monoxide) may also be used, as may oxidative gases (e.g., oxygen or carbon dioxide) depending on how the plasma is to be utilized.
Plasma generators, including those used in conjunction with, for example, plasma torches, plasma jets and plasma arc reactors, generally create an electric discharge in a working gas to create the plasma. Plasma generators have been formed as direct current (DC) plasma generators, alternating current (AC) plasma generators, radio frequency (RF) plasma generators and microwave (MW) plasma generators. Plasmas generated with RF or MW sources are called inductively coupled plasmas. For example, an RF-type plasma generator includes an RF source and an induction coil surrounding a working gas. The RF signal sent from the source to the induction coil results in the ionization of the working gas by induction coupling to produce the plasma. DC and AC type generators may include two or more electrodes (e.g., an anode and cathode) with a voltage applied between them. An arc may be formed between the electrodes to heat and ionize the surrounding gas such that the gas obtains a plasma state. The resulting plasma may then be used for a specified process application.
Plasma reactors can be used for the high-temperature heating of material compounds to accommodate chemical or material processing. Such chemical and material processing may include the reduction and decomposition of hazardous materials. In other applications, plasma reactors have been utilized to assist in the extraction of a desired material, such as a metal or metal alloy, from a compound that contains the desired material.
Process applications utilizing plasma generators are often specialized. Consequently, the associated plasma reactors need to be designed and configured according to highly specific criteria. Such specialized designs often result in a device with limited usefulness. In other words, a plasma reactor which is configured to process a specific type of material using a specified working gas is not likely to be suitable for use in other processes wherein a different material is being processed using a different working gas.
In view of the shortcomings in the art, a need exists for a plasma reactor and associated system that has adjustable controls and provides improved flexibility regarding the plasma being generated. For example, it would be advantageous to provide a plasma reactor and system that enables the direct processing of solid materials into a gaseous state. It would further be advantageous to provide a plasma reactor and associated system which produces an improved arc and associated plasma column or volume wherein the arc and plasma volume may be easily adjusted and defined to optimize a plasma. These needs are met by the present invention as described and claimed below.